Theresa May with members of her cabinet. Debate on her withdrawal agreement will resume in parliament on 9 January.
Photograph: Reuters

Theresa May has been in contact with EU leaders over Christmas to try to seek the reassurances she hopes will persuade enough MPs to back her Brexit deal in January, Downing Street has said.

“She has been in contact with European counterparts over the break, and you can expect more of that to continue over the week,” the prime minister’s spokeswoman said.

“I haven’t got a list for you, but she has been in touch with European leaders, and that will continue in the lead-up to the vote.”

MPs will resume debating May’s proposed Brexit deal on 9 January, with the vote due to take place the following week. It had been scheduled for December, but the prime minister postponed it at the last minute, amid near-unanimous expectations that she would lose heavily.

She delayed the vote to placate MPs by seeking what Downing Street calls “legal and political assurances” over the deal, notably on the backstop arrangement for the Irish border.

The backstop, which would keep Northern Ireland in elements of the single market and customs union if no permanent trade arrangement is reached to avoid a hard Irish border, is heavily disliked by May’s DUP allies, as well as by a number of Brexit-backing Conservative MPs.

They are concerned that the UK would not be able unilaterally to pull out of the arrangement, something on which the EU is refusing to budge. May has hoped to gain assurances that the backstop is unlikely to come into force.

The Christmas talks had not yet led to a solution, May’s spokeswoman said: “There’s still more work to do. The PM is absolutely focused on doing that in the lead-up to the vote itself. The UK team, at official level, are in contact with their counterparts in the EU technical level. Her focus is on getting the assurances MPs want ahead of that vote taking place.”

Asked if the prime minister was confident of success, given the resumption of the Commons debate begins in little more than a week, the spokeswoman said: “That is what she is focused on, yes.”

Parliament returns on 7 January, and May will hope to persuade the DUP and potential Tory rebels to back her plan, arguing that if her plan is blocked, Brexit might not happen.

One leading Conservative malcontent, John Redwood, was knighted in the New Year honours list, prompting accusations of desperate tactics by No 10. He has since said it will make no difference to his vote.

Downing Street has also sought to exert pressure on remain-leaning MPs by insisting that a no-deal departure is the alternative to her proposal, and ramping up contingency planning for this.

This has included spending more than £100m to charter ferries to ease “severe congestion” at Dover in the event of a no-deal Brexit. It has emerged that one of the companies contracted, Seaborne Freight, does not own any ships, has not previously operated a ferry service and is not planning to do so until late March.